android - Is the procedure correct to write Characteristic in Bluetooth Low Energy? -

i have button in mainactivity used write byte[] ble device:

<button     android:layout_width="match_parent"     android:layout_height="wrap_content"     android:text="write char"     android:id="@+id/button2"     android:onclick="onclickwrite" /> 

and function onclickwrite is

public void onclickwrite(view v){     if(mbluetoothleservice != null) {        byte [] data= new byte[3];        data[0] = (byte)(0 & 0xff);        data[1] = (byte)(255 & 0xff);        data[2] = (byte)(0 & 0xff);        mbluetoothleservice.senddata(data);     } } 

where senddata modified function in class [bluetoothleservice][1]. worked when press button. however, let careful @ senddata function. searches service , characteristic again when press button. correct procedure write characteristic in ble?

public void senddata(byte[] data){     string lservice = "00001c00-d102-11e1-9b23-00025b00a5a5";     string lcharacteristic = "00001c03-d102-11e1-9b23-00025b00a5a5";     bluetoothgattservice mbluetoothleservice = null;     bluetoothgattcharacteristic mbluetoothgattcharacteristic = null;      (bluetoothgattservice service : mbluetoothgatt.getservices()) {         if ((service == null) || (service.getuuid() == null)) {              log.d("tag","something null");             continue;         }         if (lservice.equalsignorecase(service.getuuid().tostring())) {              log.d("tag","service.getuuid().tostring()="+service.getuuid().tostring());             mbluetoothleservice = service;         }     }     if(mbluetoothleservice!=null) {         mbluetoothgattcharacteristic =                 mbluetoothleservice.getcharacteristic(uuid.fromstring(lrgbcharacteristic));     }     else{         log.d("tag","mbluetoothleservice null");     }      if(mbluetoothgattcharacteristic!=null) {         mbluetoothgattcharacteristic.setvalue(data);          boolean write = mbluetoothgatt.writecharacteristic(mbluetoothgattcharacteristic);          log.d("tag","writecharacteristic:"+write);     }     else{         log.d("tag", "mbluetoothgattcharacteristic null");     } } 

yes.

(filling unnecessarily required length)